D2 and Q4 orbit corrector status J. Rysti, E. Todesco, G. Kirby 25/2/2015
Design proposal 25/2/2015
Multipoles (both on) Ref. radius 2/3 of aperture = 35 mm + few possible units from manufacturing & assembly Both apertures powered. 2 layers, 20 mm collars. Max 1850 A. 25/2/2015
Multipoles (1 on & 1 off) 1 2 One aperture powered at a time 2 layers, 20 mm collars Max 1850 A 25/2/2015
Other options Presented baseline has: If only 1 layer: Self-supporting 20 mm collars (?). 2 layers, 1.7 kA, 45 % I/Iss, 2.8 T bore field. If only 1 layer: 25 mm collars or more iron => 3 T is achievable. Need 3.5 kA current, 70 % I/Iss (2.8 T). Use also the rigidity of the yoke: Reduce collar thickness & gain more iron. 15 mm collars & 2 layers => can go to 3 T. 25/2/2015
Coil ends 25/2/2015
Q-protection Straightforward. Dump or CLIQ. Dump resistor & switch for this range needs development. 1.8 kA, 40 mΩ dump resistor,15 ms delay, Earth: central dump Green: voltage Red: hot spot T Blue: current Purple & cyan: average T 25/2/2015
Extra slides Increase yoke diameter 452 mm => 570 mm. 1 layer, iron yoke, 25 mm collars, 3 T, H/V. Problem: required current 3.5 kA. JNbTi = 2900 A/mm2 (~50% SSL) B = 2.86 T & 2.92 T I = 3450 A B = 3.00 T & 3.00 T 25/2/2015
Extra slides Jc,NbTi = 6200 A/mm2 @ 3.5 T, 1.9 K 25/2/2015
Multipoles (25 mm collar) Ref. radius 2/3 of aperture 2 layers 25 mm collars Max 1750 A 25 mm collars too much 25/2/2015
Preliminary mechanical analysis 1 layer. 25 mm collars. Max. radial displacemen at 3T is 37 µm. Max stress < 70 MPa (need to model keys etc.). Self supporting collars OK. 25/2/2015
Yoke size To reduce the weight and cost, make yoke as small as possible. Multipoles reach 10, when yoke diam. 540 mm. => yoke area 87 % of 570 mm case. Elliptical yoke 588mm x 452mm => 78 % (is it enough that individual multipoles < 10 ?) If maximum rotated multipoles < 10 => 81 %. With additional holes and/or cuts can reduce slightly more. 25/2/2015
Conclusions ? 25/2/2015